Fluid pulsation dampener



June 16, 1964 E w. s. EVERETT ETAL 3,137,316

FLUID PULSATION DAMPENER Original Filed May 17, 1962 l I9 s g b g S 21as 24 z a z 29 3| grao ATTORNEYS United States Patent;

3,137,316. FLUID PULSATION DAMPENER Wilhelm S. Everett, 126 W. SantaBarbara St., and John F. :ictichards, 1219 Hawthorne St., both of SantaPaula,

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Continiiation of application Ser. No. 195,624, May 17,

E62. This application Jan. 13, 1964, Ser. No. 338,560

16 Claims. (Cl. 138-26) This invention generally relates to fluidpulsation dampeners for the control of fluid surges and pulsations, andit more particularly concerns a dampener designed for di- 7 dampener mayequally Well be. applied to other analogous applications in which asudden fluid surge or pressure is built up in a fluid line as the resultof a valve closure or the like. Thus, the fluid surge dampener of thepresent invention may also be termed a device for the suppression ofwater hammer, for example.

Most conventional fluid surge dampening devices embody some type ofmoving part or parts which are sub- 'ect to fatigue or failure. Othersinvolve synthetic products which may deterioriate upon contact withcertain fluids passing through the line. Still other dampening devicesavailable on the market are of too large a size to upon closure of avalve downstream of the device, the

fluid flowing through the line will pass through the openingin thethroat section of the venturi section into the receptacle and graduallyfill the receptacle compressing the gas disposed therein (as hereafterexplained); thereafter, the fluid will return to the line by passingoutof the receptacle and back into the venturi section dissipating a partof its energy as it flows through the opening 'in the throat portion ofthe venturi section. In this regard, as a feature of the presentinvention, it is desirable that the opening be tangential to the throatportion such that a vortex action is created which tends to dissipate asubstantial amount of the pressure energy of the fluid as it returns tothe line.

During normal operation, the velocity of the fluid flowing through theventuri section causes a pressure drop at the venturi throat which inturn draws a certain volume of the fluid contained within the receptacleoutwardly .tlierefrom to in turn create a low pressure condition thereinand, consequently, open the valve to allow gas to enter the receptaclewhereby thereceptacle is charged with gas in the event of valve closureas heretofore described.

A better understanding of the present invention will be had by referenceto the drawings, showing merely one illustrativeembodiment, and inwhich:

FIGURE 1. is a partial sectional view through the improviedfluid surgedampener of the present invention;

meet the needs of many applications or are not subject to preciseengineeiing design to match the surges and fluid viscositiescharacterizing the lines towhich they are to be applied. I

It is, therefore, an important object of the present invention toprovide an improved fluid surge and pulsation dampener which is notsubject to fatigue or wear and which will not require any appreciablemaintenance over a long period of life.

Another object of the present invention is to provide a fluid surgedamp'ener which does not require or embody any synthetic materials orother materials which may deteriorate by contact with various fluids,such as gasoline, oil, or the like which may be flowing through the lineto which the dampener is coupled.

Still another object of the present invention is to provide a fluidsurge dampener which may be constructed of relatively small overalldimensions, and yet which may be precisely sized and design calculatedto match the fluid and range of surges anticipated in the line to whichit is to be connected.

Still a further object of the present invention is to provide a fluidsurge dampener which may be economically constructed of a minimum numberof parts, and yet which may be conveniently fabricated on a productionline basis.

These and other objects and advantages of the present invention aregenerally achieved by providing a fluid surge dampener designed forconnection into a fluid line for dampening surges therein. The surgedampening portion of the device comprises a closed receptacle encirclingand sealably connected to the line at two spaced points along the lengththereof. cates between the interior of the receptacle and an externalsource or" gas or air. The valve is of such a construction that it isdesigned to open in response to a given pressure drop within thereceptacle.

A venturi section is interposed in the line, and the venturi sectiondefines .a throat portion having at least one opening thereincommunicating with the interior of the receptacle.

FIGURE 2 is a crosssectional view of the venturi throat taken in thedirection of the arrows 22 of FIG- URE l; and,

FIGURE 3 is a schematic representation of a typical installation of theimproved fluid surge dampener of the present invention.

Referring now to the drawings, there is shown in FIG- URE 1 a shell 10which forms a fluid ve'sselor receptacle. The shell 10 may bemanufactured to include an .upper portion 11, an intermediate portion12, and a lower portion 13. The upper portion 11 is provided'with avalve or vacuum breaker 14, which is designed .to open in response to agiven decrease of pressure within the shell 10. The upper portion 11mayalso be provided with apressure gauge 15 merely for visual indication.of the interior pressure of the device. g V p The shell 10 in 'itsupper'section 11 is additionally provided with anopening .16 to receivean outlet line or pipe 17 which may embody at its external end a'flange18 for coupling .to.the downstream part of the line. The

tion 12 may be welded to the lower portion as indicated at 21.Preferably, backing rings 22 and 23 are provided within the shell 10 toreinforce the shell at the circular points underlying the welds 20 and21. It will be appreciated that the particular construction employed toform the spherical receptacle may be varied and that the constructionillustrated is merely one method of manufacturingthe shell '10. Also,althougha spherical construction is desired, other shapes maybe employedfor the I shell it? without materially affecting the operating results Anormally closed valve communi- With such a construction for a fluidpulsation dampener,

of the unit. p

The bottom portion "13 desirably includes a drain plug 24 ofconventional construction. It would also benoted that the vacuum breaker14, the pressure gauge 15, and the inspection plug 19 are conventionaldevices available on the market, and it is not believed that theirfurther description or explanation of operation is required orwarranted. V I

In accordance with an importantfeature of the present invention, thereis provided a venturi section 25 which Patented June 16, 1964 includes adiverging upper portion 26 which may be welded at 27 to the lower end ofthe outlet pipe 17. The venturi section includes a throat portion 28provided with at least one opening 29 communicating with the interior ofthe receptacle 10.

' As shown more clearly in the view of FIGURE 2, it is preferred thatfour radially spaced openings be provided.

It is also preferred that these openings 29 communicate tangentiallywith the interior of the throat section for a purpose that will becomeclearer as the description proceeds.

The venturi section 25 further includes a conventional convergingsection 30 which is rigidly coupled within an inlet pipe 31. The inletpipe 31 may, in turn, be provided with a flange 32 (similar to theflange 18 of the outlet pipe 17) for coupling to the downstream part ofthe line.

The operation of the improved fluid surge dampener and the advantages ofits construction may more clearly be appreciated by describing the unitas it might be installed in a conventional application. Thus, referringto FIG- URE 3, there is schematically illustrated a tank 33 which mayhave an outlet connecting with a line 34. Interposed in the line 34 is apump 35 which pumps fluid through an improved fluid surge dampeningapparatus according to the present invention, indicated by the numeral36. Downstream of the fluid surge dampener 35 is a valve 37 whichcontrols the flow of fluid into the tank 38.

As will be noted, the improved fluid surge dampener 36, according to thepresent invention, is desirably mount: ed in a vertical position suchthat gravity will tend to draw all the fluid in the shell down to thebottom of the lower shell portion 13 to the tangentially directedopenings 29 communicating with the interior of the throat section 28.

In normal operation, fluid passes through the throat section 2.8 of theventuri section 25. Such increase in velocity will create a low pressurearea in the throat section 28 in accordance with the well known theoryof a venturi. The low pressure area will in turn be communicated to theinterior of the receptacle 10 and tend to draw fluid outwardly therefromthrough the openings 29 into the line 34. Such low pressure will alsoeffect an opening of the vacuum breaker 14 to draw air into the interiorof the shell according to the particular low pressure conditionsdetermined by the velocity of the fluid flowing through the section 28,the volume of the shell, and other factors.

In some instances, it may be desirable to have the vacuum breaker 14communicate with a particular source of gas instead of with atmospherewhereby the gas being drawn into the receptacle 10 will not be absorbedinto or react with the fluid being pumped through the line 34. In suchevent, the valve 14 would be disposed in a line commuicating withanother vessel containing a particular source of gas; however, mostfluids are adaptable "to the use of air and the valve 14 is shown insuch application.

Thus, with the normal flow of fluid through the line 34 under action ofthe pump 35, the receptacle 10 will be partially full of fluid andpartially full of air according to the degree of vacuum created by fluidpassing through the venturi throat portion 28.

In response to a closing of the valve 37 downstream of the dampener 36,the kinetic flow energy of the fluid will suddenly be impeded with theresult that pressure surge will tend to occur as the fluid tends tocompress itself. At such time, the fluid in the line 34 will flowthrough the restricted openings 29 into the interior of the shell 10 tocompress the gas disposed therein. Of course, as soon as the fluid flowsinto the shell 10 and the pressure is simultaneously increased, thevacuum breaker 14 will close. The compression of the gas will create ineffect a pneumatic spring whereby the compression will continue until itequalizes the kinetic energy of the fluid; thereafter the fluid willtend to return to the line 34 by passing back through the openings 29under the expansion forces of the gas and the effect of gravity. It willbe appreciated that as the fluid passes back through the openings 29, inview of the tangential relationship of these openings to the interior ofthe throat section, a vortex will be created which will tend to absorban additional amount of energy.

Certain design considerations must be considered in order that thepulsation dampening device of the present invention function adequatelyfor a particular application. The first consideration is to ascertainthe maximum pressure permissible. Thereafter, the openings 29 aredesigned to furnish a certain degree of restriction which will in turncreate friction to fluid movement from the line 34 into the receptacleor shell 10 of the dampener 36.

The actual friction resulting from forcing the fluid through the smallopenings 29 will absorb a part of the kinetic energy of the fluid;thereafter, more of the energy of the fluid will be absorbed incompressing the gas within the shell 10.

On reverse flow, the gases will be working to force the fluid back outof the openings 29; in consequence, vortex action is necessary as afurther means of absorbing the energy of the fluid so that a reverseshock wave will not be created.

Of course, complete 'eliminatio of pressure increases is usually notnecessaiy; however, with the device according to the present invention,it has been shown through actual installations that the increase in thepressure can be decreased ten fold by using the construction such asillustratively shown in the drawings.

It will also be appreciated that the vacuum breaker 14 is not essential,although it is desirable in certain applications for most effectiveelimination of pressure surges. Thus, for example, certain liquids willvaporize as a result of a suflicient pressure drop whereby the vaporcreated eliminates the necessity of external gas or air being drawn intothe device. Further, under certain pressure conditions the bulk modulusof elasticity of the fluid compensates for the lack of the breaker.Thus, under low pressure conditions the bulk modulus of elasticity ofmost fluids decreases suflicientiy to give the fluid itself a spongycharacteristic.

A further advantage of the device according to the present invention isthat substantially no maintenance is required and assuming the unit canuse air for charging itself, no other gas or liquid connections need bemade. The only moving element is embodied in the vacuum breaker whichcan be readily replaced if required.

It will be appreciated, however, that various changes and modificationsmay be made without departing from the spirit and scope of the inventionas set forth in the claims which follow. The present invention is acontinuation-in-part of applicants co-pending patent application SerialNo. 144,456, filed October 11, 1961, and entitled Fluid PulsationDampener, and is also a continuation of applicants co-pending patentapplication Serial No. 195,624 filed May 17, 1962, now abandoned.

What is claimed is:

1. A device for dampening surge pressures in a fluid line, said devicecomprising a closed receptable encircling and sealably connected to saidline at two spaced points along the length thereof; a normally closedvalve communicating between the interior of said receptacle and anexternal source of gas, said valve being designed to open in response toa given pressure drop within said receptacle; a venturi sectioninterposed in said line, said venturi section defining a throat portion,and at least one opening in said throat portion communicating with theinterior of said receptacle.

2. A device, according to claim 1, in which said opening communicatestangentially with said throat portion.

3. A device for dampening surge pressures in a fluid line, said devicecomprising a closed receptacle encirclingand sealably connected to saidline to enclose a given portion thereof between two spaced points alongthe length thereof; a normally closed valve communicating between theinterior of said receptacle and an external source of gas, said valvebeing designed to open in response to a given pressure drop within saidreceptacle; a venturi section at least partially interposed in saidgiven portion of said fluid line, said venturi section defining a throatportion and at least one opening in said throat portion communicatingwith the interior of said receptacle.

4. A device for dampening surge pressures in a fluid line, according toclaim 3, in which said opening communicates tangentially with saidthroat portion and in which said receptacle is spherically shaped.

5. A device for interposition in a fluid line for dampening fluid surgestherein comprising: a conduit having opposing ends designed forconnection to corresponding ends of said line; a receptacle encirclingand sealably connected to said conduit at two points, respectively, nearthe opposing ends of said conduit; a normally closed valve communicatingbetween the interior of said receptacle and an external source of gas,said valve being designed to open in response to a given pressure drop.within said receptacle; a venturi section interposed at least partiallyin said conduit, said venturi section defining a throat portion and atleast one opening in said throat portion communicating with the interiorof said receptacle.

6. A device for interposition in a fluid line, accord-v ing to claim 5,in which said opening communicates tangentially with said throatsection.

7. A device for dampening surge pressures in a vertically disposed fluidline, said device comprising a closed receptacle encircling and sealablyconnected to said line at two spaced points along the length thereof; anormally closed valve in the upper portion of said receptaclecommunicating between the interior of said vessel and an external sourceof gas, said valve being designed to open in response to a givenpressure drop within said vessel, a venturi section interposed in saidline, said venturi section defining a throat portion, and at least oneopening in said throat portion communicating with the interior of thelower part of said receptacle.

8. A device for dampening surge pressures in a vertically disposed fluidline, according to claim 7, in which said opening communicatestangentially with said throat section.

9. A device for dampening surge pressures in a fluid line, said devicecomprising a closed receptacle encircling and sealably connected to saidline at two spaced points along the length thereof; a venturi sectioninterposed in portion thereof between two spaced points along the lengththereof; a venturi section'at least partially interposed in said givenportion of said fluid line, said venturi section defining a throatportion and at least one opening in said throat portion communicatingwith the interior of said receptacle.

12. A device for dampening surge pressures in a fluid line, according toclaim 11, in which said opening com- 'municates tangentially" with saidthroat portion and in' which said receptacle is spherically shaped 13. Adevice for interposition in a fluid line for dampening fluid surgestherein comprising: a conduit having opposing ends designed forconnection to corresponding ends of said line; a receptacle encirclingand sealably connected to said conduit at two points, respectively, nearthe opposing ends of said conduit; a venturi section interposed at leastpartially in said conduit, said venturi section defining a throatportion and" at .least one opening in said throat portion communicatingwith the interior of said receptacle.

14. A devicefor interposition in a fluid line, according 'to claim 13,in which saidopening communicates tangentially with said throat section.I I

15. A device for dampening surge pressures in a vertically disposedfluid line, said device comprising a closed receptacle encircling andsealably connected to said line at two spaced points along the lengththereof; a venturi section interposed in said line, said venturisectiondefining a throat portion, and at least one opening in saidthroat portion communicating with the interiorof the lower part of saidreceptacle. 7 I

16. A device for'dampening surge pressures in a vertically disposedfluid line, according to claim 15, in which said opening communicatestangentially with said throat section.

References Cited in the file of this patent UNITED STATES PATENTS2,896,862-- Bede July 28, 1959 2,904,076 Engel et al. Sept. 15, 19593,018,799

Volkmann et al. Jan. 30, 1962 McCullough Mar. 9, 1954*

1. A DEVICE FOR DAMPENING SURGE PRESSURES IN A FLUID LINE, SAID DEVICECOMPRISING A CLOSED RECEPTABLE ENCIRCLING AND SEALABLY CONNECTED TO SAIDLINE AT TWO SPACED POINTS ALONG THE LENGTH THEREOF; A NORMALLY CLOSEDVALVE COMMUNICATING BETWEEN THE INTERIOR OF SAID RECEPTACLE AND ANEXTERNAL SOURCE OF GAS, SAID VALVE BEING DESIGNED TO OPEN IN RESPONSE TOA GIVEN PRESSURE DROP WITHIN SAID RECEPTACLE; A VENTURI SECTIONINTERPOSED IN SAID LINE, SAID VENTURI SECTION DEFINING A THROAT PORTION,AND AT LEAST ONE